transform_collection.cpp

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/*
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#include <mongo_ros/transform_collection.h>
#include <boost/foreach.hpp>
#include <boost/format.hpp>

namespace mongo_ros
{

namespace gm=geometry_msgs;
using std::string;
using std::vector;
using boost::format;


// We'll look at all transforms between t-history_length and t+INC
const double INC=1.0;
  
mongo::Query TransformCollection::transformQuery (const double t) const
{
  format query("{stamp : { $gte : %.9f, $lte : %.9f } }");
  const double start = t-history_length_;
  const double end = t+INC;
  string s = (query % start % end).str();
  mongo::Query q = mongo::fromjson(s);
  return q;
}

tf::StampedTransform TransformCollection::lookupTransform (const string& target,
                                                           const string& src,
                                                           const double t) const
{
  // Form the query
  const mongo::Query q = transformQuery(t);

  // Iterate over the messages and add them to a Transformer
  tf::Transformer buffer(true, ros::Duration(history_length_+INC*1.1));
  typedef MessageWithMetadata<tf::tfMessage>::ConstPtr MsgPtr;
  BOOST_FOREACH (MsgPtr m, coll_.queryResults(q)) 
  {
    BOOST_FOREACH (const gm::TransformStamped& trans, m->transforms) 
    {
      const gm::Vector3& v = trans.transform.translation;
      const gm::Quaternion& q = trans.transform.rotation;
      const std_msgs::Header& h = trans.header;
      const tf::Transform tr(tf::Quaternion(q.x, q.y, q.z, q.w),
                             tf::Vector3(v.x, v.y, v.z));
      const tf::StampedTransform t(tr, h.stamp, h.frame_id,
                                   trans.child_frame_id);
      const bool ok = buffer.setTransform(t);
      ROS_ASSERT_MSG(ok, "Tf setTransform returned false for transform from %s "
                     "to %s at %.4f", trans.child_frame_id.c_str(),
                     h.frame_id.c_str(), h.stamp.toSec());
    }
  }
  tf::StampedTransform result;
  buffer.lookupTransform(target, src, ros::Time(t), result); // Can throw
  return result;
}


tf::StampedTransform LiveTransformSource::lookupTransform (const string& target,
                                                           const string& src,
                                                           const double tm) const
{
  ros::Time t(tm);
  tf_->waitForTransform(target, src, t, ros::Duration(timeout_));
  tf::StampedTransform trans;
  tf_->lookupTransform(target, src, t, trans); // Can throw
  return trans;
}

} // namespace